# coding=utf-8
import requests
import re
from lxml import etree
import time
import sys
reload(sys)
sys.setdefaultencoding("utf-8")

#定义一个爬虫
class spider(object):
    def __init__(self):
        print u'开始爬取内容。。。'

#getsource用来获取网页源代码
    def getsource(self,url):
        html = requests.get(url)
        return html.text

#changepage用来生产不同页数的链接
    def changepage(self,url,total_page):
        now_page = int(re.search('index_(\d+)',url,re.S).group(1))   #可修改
        page_group = []
        for i in range(now_page,total_page+1):
            link = re.sub('index_\d+','index_%s'%i,url,re.S)       #可修改
            page_group.append(link)
        return page_group

#getpic用来爬取一个网页图片
    def getpic(self,source):
        selector = etree.HTML(source)
        pic_url = selector.xpath('//ul[@class="ali"]/li/div/a/img/@src')   #可修改
        return pic_url

#savepic用来保存结果到pic文件夹中
    def savepic(self,pic_url):
        picname=re.findall('(\d+)',link,re.S)    #可修改
        picnamestr = ''.join(picname)
        i=0
        for each in pic_url:
            print 'now downloading:' + each
            pic = requests.get(each)
            fp = open('pic\\'+picnamestr +'-'+str(i)+ '.jpg', 'wb')
            fp.write(pic.content)
            fp.close()
            i += 1

#ppic集合类的方法
    def ppic(self, link):
        print u'正在处理页面：' + link
        html = picspider.getsource(link)
        pic_url = picspider.getpic(html)
        picspider.savepic(pic_url)

time1=time.time()
if __name__ == '__main__':
    url = 'http://www.ivsky.com/tupian/ziranfengguang/index_1.html'   #可修改
    picspider = spider()
    all_links = picspider.changepage(url,3)     #可修改
    for link in all_links:
        picspider.ppic(link)
time2=time.time()
print u'耗时:'+str(time2-time1)


